Started work on exposing model parameters to canvas GUI.
Updated header/comment formatting in type_descio.h.
Fixed some warnings in error.c.
A bug still exists error_reporter_tree_start that is causing problems with the
canvas-based GUI.
Added Info class to canvas code, for output of debug information via GUI.
Added a few missing types of gtksourceview langdef.

Add steps to converge rankine_regen (still problematic).
Fixed 'rename' tool in canvas model so that Enter key works.
Added Export as SVG support in blocklist.py.
In PyGTK GUI, "Fixed variables" dialog now includes the values (no units yet).
Graphviz view of system now attempts to show unconverged relations (ongoing).